Synthetic lubricants



Patented Mar. 14, 1950 UNITED STATES PATENT OFFICE SYNTHETIC LUnaIcAN'rs Harry G. Doherty and Alexander N. Sachanen, Woodbury, and Francis M. Seger, Pitman, N. 1., asaignors to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application April 8, 1949,

Serial No. 86,384 I 11 Claims.

' cosity index, relatively low pour point and satisfactory stability. The process there described involves a thermal, non-catalytic conversion of normal, alpha mono-olefins having between about six and about twelve carbon atoms per molecule. Temperatures of operation range from about 500 F. to about 750 F., preferably from about 600 F. to about 700 F.

Although good yields of these desirable synthetic lubricants are obtained by so treating the aforesaid oleflns at temperatures lower than about 700 F., the residence or reaction times required to produce commercially feasible yields is excessively long. As disclosed in the aforesaid copending application, however, yields-of synthetic lubricants and the viscosity indices thereof diminish substantially as the temperature is raised above 700 F. and secondary reactions are initiated. Secondary reactions which are considered to be involved at the higher temperatures are:

(1) Degradation or cracking, as evidenced by decrease in oil yields;

(2) Cyclization begins, as evidenced by a decycle in viscosity index with accompanying increase in gravity and refractive index; and

(3) Volatile non-oily components of the reaction mixture become progressively more saturated, as indicated by a decrease in bromine ada dition number and, therefore, less suitable for recycling for further conversion.

As a substantial improvement over the afore- MiG-683.1)

2 said process, it has now been discovered that synthetic lubricants possessing the combination of desirable properties referred to above, can be produced at temperatures greater than about 700 F. in good yields and in relatively short time periods. The present process comprises treatment of a normal, alpha mono-olefin having between about six and about fourteen carbon atoms per molecule, inthe absence of catalytic material and in the presence of a minor and eflective proportion of a paraflinic hydrocarbon, at temperatures greater than about 700 F. and not substantially above about 850 F. for relatively short reaction or residence times.

NORMAL, ALPHA MONO-OLEFINS As indicated above, the mono-olefins of this invention are normal or straight chain alpha mono-olefins and contain between about six and about fourteen carbon atoms per molecule. Such mono-oleflns are normally liquid at temperatures of the order of 20-25 C. Illustrative of such mono-oleflns are the following: hexene-l, octene- 1, decene-l, dodecene-l, tetradecene-l, and the like. Preferred, however, are those having from eight to twelve carbon atoms, with decene-l representing a particularly desirable olefin. It will be clear from the foregoing examples than an alpha olefin may also be referred to as a l-olefln.

Not only may the mono-olefins of the aforesaid character be used individually in this invention, but they may also be used in admixture with each other. In addition, olefin mixtures containing a substantial proportion of such mono-olefins may be used. Preferred of such mixtures are those containing a major proportion of a l-olefin or of l-olefins. In general, the charge stock preferably should contain less than about 20% by weight of unsaturated hydrocarbons other than straight chain l-olefins. Representative of such mixtures are those obtained by the cracking of paraflln waxes and other paraffin products; those obtained from the Fischer- Tropsch and related processes.

These hydrocarbon mixtures may contain, in

addition to' the l-olefin or l-olefins, such materials as: other olefins, parafilns, naphthenes and aromatics.

In many instances, ineommercial operation,

it will be found desirable to use technical grades .of l-olefins. Mixed olefinic materials derived from thermal cracking of hydrocarbon wax or from the Fischer-Tropsch process constitute satisfactory charging stocks. In this connection, it

must be noted that it is suspected that substantially straight chain l-olefins, that is, l-olefins in which the length of the side chain (or chains) is short relative to the length of the main chain. and in which the side chain (or chains) is not adjacent to the terminal double bond, are also suitable, although iess advantageous charge stocks for the purpose of the present invention. In view of the unavailability of such olefins. however, no test data can be adduced to confirm this suspicion.

PARAFFINS The chain length of the paramn hydrocarbon as is preferably varied with the temperature of operation. It has been found, for example, that 4 tion of paramn inhibitor previously discussed. The pressure to be used, however, is not particularly critical. It may range from about 100 to about 4,000 pounds per square inch, or even a higher.

As indicated above, the present process is a thermal, non-catalytic process related to that described in said co-pending application Serial No. 761,716. The process is described as non-catalytic inasmuch as polymerization or condensation catalysts are not used. For example, Friedel-Craftl type catalysts such as aluminum chloride have hitherto been used to polymerize oIefins under the relatively short-chain parafllns, such as propane, butanes and pentanes, while effective at temperatures of the order of about 750-850 F., are more advantageous at temperatures of about 850 F. The longer-chain parafllns are advanconditions differing considerably from those recited above. It is with this in mind that the present process is described as non-catalytic.

In order to illustrate the principles of this invention, the results of a series of typical, and non-limiting, conversions are set forth in tabular form in the several tables shown below. These conversions were carried out in rocking-type bombs (American Instrument Co.). The olefins and parafiln inhibitors were charged to the bombs. The bomb heads were secured andthe bombs were flushed with nitrogen to displace air present therein. The bombs were then heated (while rocked) to the desired temperature for the desired length of time. Thereafter, the bombs were discharged either immediately by passing the hot 7 reaction products through a'condensing system,

or after the reaction products had cooled to about 60-80 F. in the bomb.

It should be noted that the reaction times, recited as Time, hours" in the tables, represent the timeintervals during which the bombs were maintained at the desired temperature, and do 40 not include the time intervals necessary to heat tageous at temperatures from about 700 1''. to,

about 750 F., their effectiveness decreasing with rising temperature.

With regard to the concentration of the parafiln inhibitor or retardant, minor amounts as low as about 0.1 per cent to about per cent may be used. The proper amount of inhibitor or retardant will depend largely on the parafiin selected and the operating conditions. For example, pentanes have been found to be effective in concentrations from about 3% to about 50%, whereas paramn wax is most advantageous in concentrations of one per cent or less due to its influence upon the pour point of the residual" oil. Preferably, however, minor amounts of the order of .about one to about 30% of the total charge are most effective.

REACTION CONDITIONS The relatively high temperature and relative short reaction times of operation used in the present process, vary inversely with each other. When temperatures of the order of about 700- "750' F. are used, reaction times are preferably the bombs and their contents to the desired temperature, and do not include the time intervals necessary to cool the bombs after heat to the bombs has been discontinued. In general, about i one and one-half hours are required to raise the temperature from 60-80" F. to 750 n, and about eight hours to cool thereafter to 60-80 F., in runs such as shown in the tables. However, since it has been shown in said copending application Serial No. 761,716 that substantially no polymerization occurs below 500 F., these times are of little significance. The experiments compared in the tables were made under directly comparable conditions.

The condensation products discharged from the bombs were vacuum topped to remove any unreacted hydrocarbon material and any relatively low boiling products and then were filtered, as in the runs shown in the tables. To distinguish the condensation products from the distillate fractions thereof, the refined oils are identified as residual oils. The latter term identifies the oils from which unreacted materials and products TABIE I Conversions at 750 F. with and without n-pentane mm No 1 2 s 4 I a o Olefin Ch d l-deoene... l-deoene-.- l-deeene... l-decene... i-deoene.

Parts b 40 400 740 700 388. Inhibitor C None- None--- None Nonen-pentano.

Parts by weight 12.

Wt. D Reaction Time, Hrs. Mex. Pressure, p. s. i. g Residual Oil' ye ls, w}. Per Cent Olefin Charged--- ifieciilc Gravity N N 0.1. 0.5...... Color (Lovibond) 1 3.7. Carbon Residue (Ramsbottom) 0.0 0.01.

Run No 7 8 9 10 11 12 Olefin Charged l-deoene... l-decene... 1-decene 1-deeene. l-deoene.-. l-deoene.

Parts by weight- 388 388 388 420 280 200.

Inhibitor Charged. n-pentane. u-pentanen-pentane. n-pentano. n-centane.

Parts by weight.-. 12 12 24 144 200.

Wt. per cent charge 50.

Reaction Time, Hr 2 3.

Max. Pressure, p. s. i. g 1200.

Residual Oil:

gielld, Wt. Per Cent Olefin Charged Viscosity 3'566 Viscosity 210 F., Cs Pour Point, "F

S ific Gravity 0 8314, I N 0.2. Color (Lovibond) 1.9.- 1.0. Carbon Residue (Ramsbottom) .02 0 Nil.

1 V. L's above 140 are extrapolated 'velues.

The results shown above in Table I demoncentration; 5.4 per cent provides a somewhat strate the appreciable improvement realized with an inhibitor, n-pentane, at 750 F. Runs 2-5 compared with runs 6-9 reveal the improvement obtained with n-pentane at different reaction times. By way of illustration, runs 1 and 6, 2-3

higher yield than either 3, 34 or 50 per cent.

The series of runs set forth in Table II serve to indicate the influence of higher temperatures upon the conversion of l-decene to synthetic lubri- 40 cants.

TABLE II Conversions at higher temperatures Run No 1 2 3 4 5 Olefin Charged.-. l-decene l-dodecene.

Parts by weig 388 388.

Inhibitor Charged n-pentane.

Parts by weight 12.

Wt. per cent char-2e Reaction'lemp., "F

Reaction Time, Hrs

Max. Pressure, p. s. i. 2 Residual Oil:

Viscosity 100 F., C5,.

4.7 Below Zero Below Zero 1738 195.6

Viscosity 210 F., Cs 24.87 10.86 Pour Point, T...

Specific Gravity N. N 0.8.. Color (Lovibond) Carbon Residue (Ramsbottom) 1 Value could not be obtained due to excessive foaming.

and 8 reveal a substantial improvement in yield and V. I. It appears that considerably better yields are obtained when the reaction time is from about one to about four hours; and that V. I. is relatively constant with a reaction time of less than about ten hours, and then diminishes.

The results shown in Table 11' above, demon- 7 strate the appreciable improvement in both yield and V. I. realized with an inhibitor, n-pentane, at 850 F.

Table III shows a series of runs made with and without another inhibitor, propane in the form Runs 8-12 indicate the influence of inhibitor con- 76 of a propane-propene mixture.

TABLE III Conversion at Various Temperatures with and without propane-propene mixture 1 Run No 1 2 3 4 6 6 1 l Olefin Charged l-deeene.-.. l-decene... l-deoene-.. 1-decene..... 1-decene..-. l-deeene..- l-deeene... l-deoene.

Parts b weigh M 400 700 388 388. Inhibitor C ged..- None None Parts by weight 125 1 12.

Wt. per cent diargem. 160...-.. 3.7 3.0. Reaction Temperature, R 850 852 7 2 805 852. Reaction Time, Hours..." 3 K M 3 2 34. Max. Pressure, p. s. i. g.-. 2500 N0 800 400 500. Residual Oil:

Yield. Wt. Per Cent Olefin Charged 6.3..

V. I Zero Viscosity 100 F., 0:.

Viscosity 210 F., Cs.

Pour Point, F

S iilc Gravity Color (Lovibond).

Carbon Residue (Ramsbottom)- l Commercial product containing propane and propane in about -50 concentration.

While substantial improvement inv yield and V. I. is obtained with the propane inhibitor at '750-800 F., as shown by comparison of runs 1-3 and 6-7, the improvement realized at 850 F. is oi an extremely high order: animprovement of several hundred per cent in yield and more than 145 V. I. units.

The eflect of various paraflins is shown by the series of runs in Table IV.

25 From these results, it appears that a paramn having from about three to about five carbon atoms per molecule provides optimum improvement in yield and V. I.

As pointed out hereinabove, there is no need 0 for an inhibitor when a l-olenn is treated at temperatures below about 700 F. This is demon- TABLE IV Conversions at 750 F. using various 211111117 Run No l 2 4 5 6 7 Olefin Charged l-deeene... l-deoene l-deeene l-deeene... l-deeene. i-decene..- l-decene Partsb weight... 740 400 560 388 388 286 96.

Inhibitor-C argued" ield, Wt. Per Cent Clharged visa-surefire," Viscosity 210 F., C gourgoiat. 3;

Peel c ravi L N Color (Lovibond) Carbon Residue 1 This value was extrapolated from V. I. Table.

Runs 3-7 in which an inhibitor was used, all strated byth'e series of runs presented in Table show improvement over the blank runs 1 and 2. Vbelow.

TABLE V Conversions at 650 F.10 hrs. reaction timevarious inhibitors Run No 1 2 3 4 5 6 7 Wt. percent char Residual Oil:

gielld Wt. Percent Olefin Charged. Viscosity F., C Viscosity 210 F., Cs. Pour Point, F specific Gravity.

l-dccenc... l-decene... 1-deoeue. 679 350 200 N Color (Lovibond) Carbon Residue (Rnmsbottom) I V. L's above are extra lated values.

1 Actual temperature for t a run 660' F., actual time 11 hours.

by a comparison of runs 1 and 3, 5, 6 and 7.

In addition to yield and V. I. improvements realized with the present process, lubricating 011 output, based upon reactors of equal size, may be substantially increased. As will be readily recognized, this is a factor of major importance in l0 typified by polypropylenes, polyisobutylenes, polyacrylate esters, and the like.

contemplated also as within the scope of this invention is a method of lubricating relatively moving surfaces by maintaining therebetween a film consisting of any of the aforesaid oils.

It is to be understood that the foregoing description and representative examples are nonlimiting and serve to illustrate the invention,

commercial operations. Increase in oil output is m which is to be broadly construed in the light of accomplished by a substantial reduction in resithe language of the appended claims. dence time. This relationship is shown by the We claim: results tabulated below in Table VI. 1. The method for preparing a viscous oil from TABLE VI Conversions with I-decene Charge 011 Yield 1 3, ,9 2; .F fj fi ffg Inhibitor zjgfi Units of Wt. v.1 per hour per hour 0.10 0. 0415 142 0.10 0. 0645 145 0.10 0. 0669 150 0. s3 0. 113 142. 5 0.33 0.100 116.4 0. as 0.140 112. 2 0.33 0.176 133.21 0.33 0.151 142 0. 50 0.132 123.1 0.50 0.119 126.6 2. 0 0.126 Below Zero 2.0 0.692 145 PropanePropene mixture; 50-50% reaction time.

3 Obtained by multiplying weight of Residual Oil by units of weight per hour. As will be evident from the data presented a normal, alpha mono-olefin having from about above in Tables I to VI, the condensation products of this invention are highly desirable lubricants per se. They are also of considerable value as blending agents for other lubricating oils. They impart desirable viscosity index (V. I.) and pour point characteristics to the oils in combination therewith, for, as indicated above, they have advantageous viscosity index and pour point properties. In short, the synthetic oils find utility in upgrading other lubricants. Typical oils with which the synthetic oils may be blended are mineral oils such as are normally used in internal combustion and turbine engines. When so blended, the synthetic oils may comprise the major proportion of the final blended oil, or may even comprise a minor proportion thereof.

One or more of the individual properties of the synthetic lubricants of this invention may be further improved by incorporating therewith a small, but effective amount, of an addition agent such as an antioxidant, a detergent, an extreme pressure agent, a foam suppressor, a viscosity index (V. I.) improver, etc. Antioxidants which may be used are well known in the art, and are generally characterized by phosphorus, sulfur, nitrogen, etc. content; representative of such materials is a phosphorusand sulfur-containing reaction product of pinene and P285. Typical detergents which may be so used are metal salts of alkyl-substituted aromatic sulfonic or carboxylic acids, as illustrated by diwax benzene barium sulfonate and barium phenate, barium carboxylate of a wax-substituted phenol carboxylic acid. Extreme pressure agents are well known; illustrating such materials are numerous chlorine and/or sulfur containing compositions, one such material being a chlor-naphtha xanthate. Silicones, such as dimethyl silicone, may be used to illustrate foam suppressing compositions. Viscosity index improving agents which may be used are six to about fourteen carbon atoms per molecule, which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essentially of said olefin in the presence of a minor and effective amount of a paraffin, at a temperature greater than about 700 F. for a period of time from about three hours to about one hour, and less than about 900 F. for a period of time from about one-half hour to about one-quarter hour.

2. The method for preparing a viscous oil from a normal, alpha mono-olefin having from about six to about fourteen carbon atoms per molecule, which comprises: thermally and'non-catalytically heating a hydrocarbon charge consisting essentially of said olefin in the presence of a minor and effective amount of a paraflin, at a temperature greater than about 750 F. for a period of time from about three hours to about one hour, and less than about 850 F. for a period of time from about one-half hour to about one-quarter hour.

3. The method as defined by claim 1, wherein the normal, alpha mono-olefin contains from about eight to about twelve carbon atoms per molecule.

4. The method as defined by claim 1, wherein the normal, alpha mono-olefin is n-decene-l.

5. The method as defined by claim 1, wherein the paraffin contains from about three to about five carbon atoms per molecule.

6. The method as defined by claim 1, wherein the amount of paraffin is from about one per cent to about thirty per cent.

'7. The method for preparing a viscous oil from n-decene-l, which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essentially of said olefin in the presence of about three per cent by weight of n-pen- Y i; g -i: 500,105

consisting essentially of said oleiln in the presence of about thirty per cent by weight of n-bu-' tane, at a temperature of about 750' I". for about three hours. 7 I

9. The method for preparing a viscous oil from n-decene-i, which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essentially of said olefin in the pressaid normal, alpha mono-olefin, in the presence of a minor and eflective amount of a paramn, at a temperature greater than about 700 F. for a period of time from about three hours to about one hour, and less than about 900 F. for a period of time from about one-half hour to about onequarter hour.

11. The method for preparing a viscous oil from a normal, alpha mono-olefin having from about six to about fourteen carbon atoms per molecule,

which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essen- Hall! of 'said-oleiin in-the-presonce'of a minor I and eflectiveamount'oi a ataItemperagre'ater than about 700"! i'or'aperiod of timeifrom about three hours to about "one hour,

and less than about 900 F. for a period of time from about one-half hour to about one-quarter hour. at the higher operating temperatures said paramn having from about three to about five carbon atoms per molecule and at the lower operating temperatures said paraflln having longer carbon chain length.

HARRY G. DOHERTY. ALEXANDER N. SACHANEN. FRANCIS M. SEGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,442,440 Scoville June 1, 1948 OTHER masons Eglofl', The Reactions of Pure Hydrocarbons, published by Reinhold Pub. Corp. (1937), pages 360-368.

Tilichezev et al., Pro. Conference on Cracking, Eng. Trans. in 260-683, pages 1-4 pertinent.

Nemtzev et al., Jour. Gen. Chem, vol. VIII. pages 1314-24 (1938) Eng. Trans. in 260483.15, pages 17 pertinent.

Certificate of Correction Patent No. 2,500,165

HARRY G. DOHERTY ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 29, for isoctane read isooctane; columns 7 and 8, Table III, last line of the eighth column thereof, for N .1. read Nil;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 26th day of December, A. D. 1950.

March 14, 1950 THOMAS F. MURPHY,

Assistant Uommz'saz'oner of Patents. 

1. THE METHOD FOR PREPARING A VISCOUS OIL FROM A NORMAL, ALPHA MONO-OLEFIN HAVING FROM ABOUT SIX TO ABOUT FOURTEEN CARBON ATOMS PER MOLECULE, WHICH COMPRISES: THERMALLY AND NON-CATALYTICALLY HEATING A HYDROCARBON CHARGE CONSISTING ESSENTIALLY OF SAID OLEFIN IN THE PRESENCE OF A MINOR AND EFFECTIVE AMOUNT OF A PARAFFIN, AT A TEMPERATURE GREATER THAN ABOUT 700*F. FOR A PERIOD OF TIME FROM ABOUT THREE HOURS TO ABOUT ONE HOUR, AND LESS THAN ABOUT 900*F. FOR A PERIOD OF TIME FROM ABOUT ONE-HALF HOUR TO ABOUT ONE-QUARTER HOUR. 